In a conventional surgery of breast cancer, dissection of axillary lymph nodes (biological tissue) is commonly performed. By such dissection of axillary lymph nodes, it is possible to prevent occurrence of a problem that gradually hardened and enlarged lymph nodes where cancer metastasis occurs cause disorders in critical areas such as nerves and blood vessels. Additionally, by conducting dissection of axillary lymph nodes, it is possible to know whether metastasis of breast cancer to lymph nodes occurs, and hence it is possible to predict systemic metastasis from the breast cancer. This also allows determination of postoperative regimen (choice of anticancer agent, need of radiation therapy).
As a technique of dissection of lymph nodes, a method called “sentinel lymph node biopsy” is conventionally known. The “sentinel lymph node biopsy” involves finding a sentinel lymph node during a surgery of breast cancer, removing it, preparing a histological specimen of the sentinel lymph node and conducting a rapid histological examination. The term “sentinel lymph node” used herein means a node, which a cancerous cell entering a lymph duct from a source lesion of the cancer reaches first. When cancer spreads to lymph nodes, metastasis to sentinel lymph nodes unexceptionally occurs. Therefore, by conducting a sentinel lymph node biopsy as described above, it is possible to determine the presence of metastasis of breast cancer to other lymph nodes. That is, when breast cancer does not spread to sentinel lymph nodes, dissection of the remaining lymph nodes is no longer necessary, whereas when breast cancer spreads to sentinel lymph nodes, dissection of a plurality of lymph nodes around the lesion is required depending on the situation. By conducting a sentinel lymph node biopsy in a manner as described above, it is possible to avoid unnecessary dissection of lymph nodes, and hence it is possible to reduce the burden on a patient.
In an exemplary procedure of the above conventional lymph node rapid histological examination in a surgery, first, a removed lymph node of elliptical spherical shape is longitudinally split in such a way that the split face becomes largest. After freezing the sections of the split lymph node, the split section is sliced into a thickness of several microns using a microtome. Then the slice of lymph node is stained with H-E (hematozylin eosin), and the stained lymph node is observed under a microscope, thereby accomplishing a rapid histological examination of lymph node. In conducting the rapid histological examination by splitting a removed lymph node into two pieces, if there is no cancerous cell in the split section of the lymph node, it could be recognized as negative regardless of presence of a trace of cancerous cell in the lymph node. For this reason, in order to decrease the probability of false recognition as “negative” regardless of presence of a trace of cancerous cell in a lymph node, conventionally, a lymph node is longitudinally split into three or more sections so as to obtain the largest split section in the splitting step of lymph node in the rapid histological examination.
Conventionally, in a step of longitudinally splitting a lymph node into three or more sections so as to obtain the largest split section in the splitting step of lymph node in the rapid histological examination, a cutting device having only one blade such as replaceable blade for microtome, razor blade or trimming knife handle adopting a replaceable blade (product of FEATHER Safety Razor Co., Ltd.) is used. One exemplary cutting device having only one blade is a pathologic trimming holder (see for example, Japanese Patent Application Laid-Open (JP-A) No. 2004-257855).
However, when the aforementioned conventional cutting device having only one blade is used in the splitting step of lymph node in the rapid pathologic assay, in order to split a lymph node into three or more sections along the longitudinal direction of the lymph node so as to obtain the largest split surface, it is necessary to repeat a cutting operation with a cutting device twice or more times. This causes a drawback that the shape of the lymph node is lost during the first operation because a lymph node is fragile and so small that the transverse length falls within the range of several millimeters to several tens millimeters. As a result, the second and later cutting operations of lymph node (biological tissue) become difficult, posing a problem that efficiency of cutting operation by which a lymph node (biological tissue) is split into three or more sections is deteriorated.